U323

U323 is a high-performance, low-cost PWM control power device designed for offline low-power boost, buck, and buck-boost applications, featuring a simple peripheral circuit with a minimal component count. The integrated high-voltage MOSFET enhances system surge tolerance. Unlike conventional PWM controllers, U323 has no fixed internal clock driving the MOSFET — the switching frequency automatically adjusts with load variations. The device employs multi-mode PWM control technology, which effectively simplifies peripheral circuit design, improves line regulation and load regulation, and eliminates audible noise during operation. Additionally, the internal peak current detection threshold automatically adjusts according to actual load conditions, significantly reducing standby power consumption at no load. U323 integrates comprehensive auto-recovery protection features, including VDD UVLO, cycle-by-cycle current limiting, output OVP, OTP, overload protection, and VDD OVP.

Applications

• Small appliance power supplies
• Industrial control

Key features

• Integrated 200V high-voltage startup circuit
• BUCK & BOOST compatible
• Standby power consumption below 50 mW
• Good line regulation and load regulation
• Integrated soft-start circuit
• Internal protection features: overload protection, cycle-by-cycle current limiting, output OVP, VDD overvoltage, undervoltage, and voltage clamp protection